With rising costs and environmental concerns associated with fossil fuels, renewable energy sources have become increasingly important. Renewable energy sources are low in aromatic content and provide a substitute for fossil fuels and a means of reducing dependence on petroleum oil. There is a growing interest in the use of aromatic lean biofuels as renewable transportation fuels.
Renewable energy sources include biofuels. Biofuels may be produced from a biomass feedstock to render pyrolysis oil (which is relatively soluble in water) and bio-oil. Biomass may also be gasified, subjected to a Fischer-Tropsch synthesis and fractionated to render low aromatic components. In addition, triglycerides may be extracted from crops or algal sources and then deoxygenated to provide renewable fuel blending components with low aromatic content. Each of these renewable energy sources may be fractionated such that one or more fractions fit into a traditional and desirable fuel boiling point range.
In addition to being used to produce a renewable energy source, a Fischer-Tropsch process may also be used to produce an aromatic lean component as a substitute for fossil fuel. Exemplary of such non-renewable distillates are non-oxygenated feedstocks (which may be derived from gasification of coal or natural gas) subjected to a Fischer-Tropsch process downstream.
All of these low aromatic distillates lack important fuel properties. For instance, refined petroleum distillate fuels need to exhibit low temperature properties in order to be suitable for the area and season in which they are to be used. For instance, when the temperature drops below the cloud point of the distillate fuel, operating difficulties may appear due to wax crystal dropout. Such operating difficulties can include the plugging of fuel filters and fuel lines. The consequences may be catastrophic. For instance, in the case of jet fuel distillate fuels, fuel filter plugging can lead to an interruption of fuel flow to the turbine engines.
The low temperature property of a distillate fuel can be reduced to some extent by adding a product with a lower wax content, such as a low wax heating oil or kerosene, or by using cold flow improver additives, which can be expensive depending on the required level of low temperature property suppression.
However, as stated above, some renewable fuels such as some bio-distillates and some Fischer-Tropsch hydrocarbons are themselves in need of an additive or admixture of some kind to reduce/suppress their low temperature properties and thereby extend their useful operating range to lower temperatures.
It should be understood that the above-described discussion is provided for illustrative purposes only and is not intended to limit the scope or subject matter of the appended claims or those of any related patent application or patent. Thus, none of the appended claims or claims of any related application or patent should be limited by the above discussion or construed to address, include or exclude each or any of the above-cited features or disadvantages merely because of the mention thereof herein.
In an aspect, there remains a need for a fuel which is aromatic lean and which may be used as an alternative to fossil fuels. Such alternative fuels need to substantially exhibit the properties of fossil fuels.
In another aspect, there remains a need for a composition produced from a renewable source, and process of using such, which is capable of reducing low temperature properties of distillates.
In still another aspect, there exists a need for improved distillate fuels having one or more of the attributes or capabilities described or shown in, or as may be apparent from, the other portions of this patent.